This invention relates to 3-point hitches for tractors or the like. More specifically, it relates to adjustable links, such as an adjustable top link employed in such hitches.
The spacing between the three points of attachment on an implement to be joined to a 3-point hitch on a tractor varies widely depending upon the nature of the implement, the manufacturer of the implement, the capacity of the 3-point hitch and the manufacturer of the tractor having the hitch. As a consequence, it has been necessary to provide a means whereby the hitch may be adjusted to accommodate the differences in implements.
Typically, the adjustment has been achieved by means of an adjustable top link in the hitch. Heretofore, such links have been formed as what may be termed an oversized turnbuckle, frequently having the capability of having its overall length varied by 12 inches or more. When extreme changes in the length of the link have been necessary, the adjustment process has been extremely time consuming. For example, if the threaded rod employed in such a link has 7 threads per inch and a change in length of 10 inches is necessary, 70 revolutions of the components of the link are required to achieve the adjustment.
In order to minimize the effort required, the prior art has employed ratchet devices in connection with the sleeves of such links. This approach, while an improvement, still requires significant effort.
Another approach has been to provide the sleeve of the link with an enlarged circular handle, frequently 12 inches in diameter or more in a plane transverse to the length of the sleeve to improve the leverage and thereby minimize the amount of force required to effect rotation and thus adjustment. Again, such means represent an improvement but, nonetheless, significant time is consumed in effecting adjustment.